[ODE] Speed of ODE's constraint method

[Erwin de Vries]

These framerates look rediculously low. Are you measuring the physics
stepping rate?

Erwin

----- Original Message -----
From: "Nate W" <coding@natew.com>
To: <ode@q12.org>
Sent: Friday, October 25, 2002 18:18
Subject: Re: [ODE] Speed of ODE's constraint method


> On Fri, 25 Oct 2002, Jason Gott wrote:
>
> > I need to implement a physics simulation that can
> > handle rag-doll type constraints (hinge, ball, but
> > probably none powered) with joint limits, and contact
> > with friction.  I need a fast method.  Is the LCP /
> > Lagrange multiplier method used in ODE fast enough for
> > interactive frame rates (> 30 fps) for a minimal
> > number of constraints/contacts?
>
> I just did some experiments with a rag doll consisting of 10 bodies, and 9
> joints - all bodies are boxes, and I use ball joints for the shoulders,
> hips, and neck, and hinges for the knees and elbows.  I have a 1.7ghz K7
> and a GeForce 3.
>
> It's like Porrasturvat, but without the stairs, just a simple ground
> plane.  With one doll, I get ~38 frames per second.  With two dolls, 25-28
> fps.  With three, 19-20 fps.  With four dolls (team dismount!), about 15
> fps.
>
> Changing the bodies to flat-ended cylinders brought the four-doll
> simulation down to 11 fps.  Changing them to capped cylinders, 6-9 fps.
>
> Bear in mind that there's some overhead in my tests due to the fact that
> they're conducted in a general purpose ODE playground rather than in an
> optimized game.  I have no idea how much overhead there is, though.  I
> don't think it's very significant, but if anyone can do a similar test I'd
> be really interested in the results.
>
> --
>
> Nate Waddoups
> Redmond WA USA
> http://www.natew.com
>
>
>
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